The existence of civilizations whose records go back that far (like China) and which do not mention any total destruction of the populace and replacement by the descendants of Noah, would also tend to invalidate literal Genesis.
Your answer may be found at
http://www.icr.org/article/how-can-chinese-dynasties-extend-back-many-thousan/
There are plenty flood mythologies all over the world, in numerous cultures.
The terms used in the Bible for “Earth and Heaven” are sometimes for a specific culture, and sometimes not literally for all of the Earth and the entire Universe.
http://www.ecclesia.org/truth/heaven-earth.html
There is plenty of evidence of very large floods in the area during mankind’s existence.
The existence of civilizations whose records go back that far (like China) and which do not mention any total destruction of the populace...
https://www.google.com/search?q=noah%27s+flood+china&